Government accused of rewriting science

A renown U.S. scientist says he is limited by the Bush administration as to who he can talk with and what he can say because of Bush's political strategies.

James Hansen, chief of NASA's top institute studying the climate, told Scott Pelley of the CBS program 60 Minutes government officials are attempting to rewrite science.

Hansen says global warming is accelerating because of human actions, specifically the burning of fossil fuels that emit huge amounts of carbon dioxide, methane, chlorofluorocarbon and other pollutants into the atmosphere.

Hansen told CBS he believes humans have approximately 10 years to reduce greenhouse gases before global warming becomes unstoppable. He says the White House is blocking that message.

"In my more than three decades in the government I've never witnessed such restrictions on the ability of scientists to communicate with the public," says Hansen.

Hansen says the Bush administration wants "to listen only to those portions of scientific results that fit predetermined inflexible positions. This, I believe, is a recipe for environmental disaster."

60 Minutes noted it had been trying to discuss the issue with the president's science advisor for months, but was finally told he would never be available.